Tell me what you think.

I found these hygrometer cure caps for mason jars on ebay and was just wondering what others think about them?

http://www.ebay.com/itm/Curing-Cap-for-Regular-and-Wide-Mouth-Mason-Jars-/171191776622?pt=LH_DefaultDomain_0&var=&hash=item27dbd3356e

I think they are expensive and unnecessary.

but cool at the same time...If they work and are air tight

They work.

I've seen them before, and was interested, but too expensive in my book.

I think I might buy a couple to try out. Wish me luck...

I got the two I ordered the other day and love them. I'm going to order more tonight!